Pressure

• What is the structure of particles in a gas?

  Particles in a gas have almost no forces between them and are free to move at high speeds in random directions.
• How does the motion of particles explain the pressure of a gas?

  The particles move in random directions and collide with the walls of a container, exerting a force that causes pressure.
• What is the equation used to calculate pressure?

  Pressure (Pa) = Force (N) / Area (m²) or $P =$$\frac{F}{A}$.
• What factor affects the average kinetic energy of gas molecules?

  The temperature of the gas affects the average kinetic energy; higher temperature means higher average kinetic energy.
• What effect does increasing temperature have on the pressure of a gas held at constant volume?

  Gas pressure will increase as the temperature increases.
• Why does pressure increase as temperature increases at a constant volume?

  As temperature increases, the kinetic energy of molecules increases, leading to more frequent collisions and greater force, thus increasing pressure.
• If gas A is at low pressure and gas B is at high pressure, what can be said about the rate of collisions in each gas?

  There are more collisions per second in gas A than in gas B; the rate of collisions is higher in A.
• Describe the force that the pressure of a gas exerts on the walls of its container.

  The net force acts at right angles to each surface of the container and increases as pressure increases.
• How does increasing the volume of a gas result in a decrease of pressure?

  Molecules become more spread out, decreasing the rate of collision and the rate of change of momentum, resulting in lower pressure.
• What can be said about the product of pressure and volume for a fixed mass of gas at a constant temperature?

  The product of pressure and volume is constant, expressed as $P \times V =$$\text{constant}$.
• What is the unit used for pressure?

  The unit used for pressure is Pascal (Pa).
• What increases when you do work on a gas?

  The internal energy of the gas increases, which can also lead to an increase in temperature.
• How do you convert between degrees Celsius and Kelvin?

  To convert, add 273 to degrees Celsius to get Kelvin.
• What is absolute zero?

  Absolute zero is −273 °C, where particles have no kinetic energy and do not move.
• What equation can be used to calculate the pressure/volume for a gas for which the mass is fixed and temperature is constant?

  The equation is $P_1 \times V_1 =$$P_2 \times V_2$.
• Why does the temperature of air inside a bike pump increase when it is pumped?

  Work is done on the gas when it is compressed, increasing its internal energy and average kinetic energy, which raises the temperature.